Water on out moon might make lunar colonization possible, but it appears that Jupiter's satellite Europa is better suited for life. A new study suggests Europa could support not just microorganisms, but complex life — and a lot of it.

Richard Greenberg of the University of Arizona will be presenting his findings on Europa today at American Astronomical Society's Division for Planetary Sciences. Europa's ability to support macrofauna — more complex organisms like animals — hinges on how much oxygen is contained in the suspected ocean beneath the moon's icy surface.

Greenberg believes that energetic particles from the sun are able to reach Europa's subterranean ocean despite that layer of ice. Because the surface of Europa is relatively impact-free, the ice is believed to be relatively new, about 50 million years. Based on this, Greenberg sets forth the idea that Europa is being constantly resurfaced, possibly with fresh materials, thanks to oxidizers at the planet's surface. He also estimates that, if there were, say, fish on Europa, and those fish used the same amount of oxygen as Earth fish, the moon's ocean has enough oxygen to support 6.6 billion pounds of such macrofauna.

Of course, just because Europa might be able to sustain life doesn't mean we'll find life there. But this does present the possibility that other bodies produce enough oxygen to support complex biological processes.